This invention relates to wideband communications and more particularly to minimizing the effects of interference in a radio receiver system utilizing an adaptive antenna array.
Any communication system is susceptible to degradation due to interfering conditions. In a wideband transmission system the carrier signal is vulnerable to interruption by natural phenomena, interference from other signals or countermeasures. Countermeasures may take the form of a variety of jamming schemes whose sole purpose is to disrupt the operation of a receiver.
A variety of techniques are currently used to decrease the effects of interference in receivers. Frequency agility, sensitivity time control, sidelobe blanking, random PRF and sidelobe cancellation are but a few of the well known techniques for countering interfering signals. Jammer signals are often non-pulsed or continuous wave and may be sinusoidal, modulated or noise like in nature.
Adaptive nulling is an often used technique for rejecting interference. Adaptive nulling rejects interference by reducing the directional sensitivity of the receiver antenna in the direction of the interfering signal. Unfortunately, current technical implementations are ineffective in countering instances when the interfering signal is at a power level near or below the noise level.
Thus, there currently exists a need for low cost interference suppression in a variety of wideband environments.